Well the situation does seem quite bad when you see people who leave fake reviews become brazen enough to actually advertise their services on Amazon itself [1]. I reported this review about 10 days ago and it's still up. The email address provided appears on hundreds of product listings [2]. When they can't even filter out nonsense like this I can only assume they put zero effort into tackling fake reviews.
...this is sad in the instance you describe because the actual seller did not request that 'advert for reviews' and it now marks their product as 'fake'. Yet the actual seller is legit and doing a great job according to 'fakespot'. Sample listing:
https://www.fakespot.com/company/ketdirect